i have a autometer 2888 tach in my truck and it needs to be recalibrated and i don't have access to a optcial tach or any thing like that, when i first installed the tach about 2 yrs ago i used a formula to calibrate it but i can't remember what it is, can anyone help my out here.

You will need to know the transmission ratios to do a proper job, but I believe 3rd is direct is it not??? like 1:1 through the transmission. That is the easiest gear to calculate in. So pick a speed and then do the calc and compare it to your tach.<br><br>Anyway you need to know your tires diameter, rear end ratio and transmission ratio to calculate your RPM at speed.<br><br>I have a spread sheet I can email you to calculate this for you, it was on either speedtweaks.com or another dodge site. BUt I can send it out if anyone is interested. Its good for calculations for tire corrections, crawl ratios, torque. All that good 4X4 stuff...LOL<br><br>Drop me a line, I would be glad to send it to you.<br><br>J-eh<br>

lil dog please by all means send me the spread sheet<br> drturf01@yahoo.com